Loss of the transcription factor MAFB limits β-cell derivation from human PSCs

Abstract

Next generation sequencing studies have highlighted discrepancies in β-cells which exist between mice and men. Numerous reports have identified MAF BZIP Transcription Factor B (MAFB) to be present in human β-cells postnatally, while its expression is restricted to embryonic and neo-natal β-cells in mice. Using CRISPR/Cas9-mediated gene editing, coupled with endocrine cell differentiation strategies, we dissect the contribution of MAFB to β-cell development and function specifically in humans. Here we report that MAFB knockout hPSCs have normal pancreatic differentiation capacity up to the progenitor stage, but favor somatostatin-and pancreatic polypeptide-positive cells at the expense of insulin-and glucagonproducing cells during endocrine cell development. Our results describe a requirement for MAFB late in the human pancreatic developmental program and identify it as a distinguishing transcription factor within islet cell subtype specification. We propose that hPSCs represent a powerful tool to model human pancreatic endocrine development and associated disease pathophysiology.

Combinatorial transcription factor profiles predict mature and functional human islet α and β cells

“…This is consistent with a recent report showing that in mice, MAFB does not compensate for MAFA loss 12 . Further, our data highlights MAFB as playing a key role in defining both β and α cell identity, in line with a recent report where MAFB deletion in human embryonic stem cells disrupted the differentiation process for both β and α cells 55 . Thus, our approach highlights how transcription factor profiles at the single cell level can be used to predict transcriptional and functional consequences of genetic manipulation, highlighting an immense power for large scRNA-seq datasets.…”

Single-Cell Transcriptome Profiling Reveals β Cell Maturation in Stem Cell-Derived Islets after Transplantation

“…Single-cell RNA sequencing (scRNA-seq) and other assays of global transcription have been used to rigorously study and uncover pancreatic identities ( Augsornworawat and Millman, 2020 ), including assessment of SC-β Cell populations in diabetic models ( Balboa et al, 2018 ; Maxwell et al, 2020 ), analysis of SC-islets from in vitro differentiation ( Pagliuca et al, 2014 ; Veres et al, 2019 ), and studying islets or islet development ( Baron et al, 2016 ; Byrnes et al, 2018 ; Enge et al, 2017 ; Hogrebe et al, 2020 ; Muraro et al, 2016 ; Russell et al, 2020 ; Scavuzzo et al, 2018 ; Segerstolpe et al, 2016 ; Velazco-Cruz et al, 2020a ; Xin et al, 2018 ). When compared to β Cells from cadaveric islets, these technologies revealed that in-vitro -derived SC-β Cells lack or have low expression of many important maturation genes, such as MAFA and G6PC2 ( Hogrebe et al, 2020 ; Pagliuca et al, 2014 ; Veres et al, 2019 ).…”

Sex-biased islet β cell dysfunction is caused by the MODY MAFA S64F variant by inducing premature aging and senescence in males

“…The human MAFA S64F :MAFB heterodimeric activator could impart a unique influence on β cells compared to the mouse MafA S64F :MafA homodimeric activator (Cyphert et al, 2019; Hang and Stein, 2011), which may explain why neuroendocrine tumors and overt hypoglycemia was not observed in aged MafA S64F/+ mice (data not shown). Notably, MAFB was recently shown to be essential for the formation of human embryonic derived β cells and insulin production (Russell et al, 2020), whereas there is no phenotype associated with the loss of MafB in mouse islet β cells except during pregnancy (Cyphert et al, 2019). Thus, we believe that it will be important to extend the analysis of MAFA S64F control to human islets both acutely in vitro and chronically after transplantation of human pseudoislets into immunocompromised mice to directly determine its effect in vivo .…”

“…While the role of MAFA or MAFB has not been analyzed directly in intact human islets, both are required for GSIS in the human EndoC-βH1 β cell line (Scharfmann et al, 2014;Scoville et al, 2015). Moreover, we have recently shown that MAFB is essential to insulin production in human embryonic stem cell derived β cells (Russell et al, 2020), which is in stark contrast to its dispensable role in rodents (Banerjee et al, 2016;Cyphert et al, 2019).…”